The Raw Material Procurement Challenges Facing Modern Tōshō: Responding to Tamahagane Supply Constraints, Depletion of Natural Whetstone Sources, and the Increasing Difficulty of Obtaining Traditional Materials

The Materials That Traditional Techniques Depend On Are Becoming Unstable

The forging technique of the Japanese sword developed over several centuries on the premise that specific raw materials would be available: tamahagane from tatara smelting, natural whetstones from deep mountain sources, and white charcoal and wood charcoal. Modern tōshō continue to use these materials, but the sustainability of each supply has come into question. When the quality and quantity of materials change, constraints arise in the expression of technique — this problem is shared as a quiet concern throughout the entire industry.

Tamahagane Supply Constraints

Tamahagane, the raw steel of the Japanese sword, is today produced almost exclusively at the Nittoho Tatara in Shimane Prefecture. Annual operations are concentrated in the cold winter months, and production volume is limited. The allocation of tamahagane available to tōshō is managed through the NBTHK, and it is not distributed equally to all tōshō.

There are voices saying that allocation is prioritized for "higher-ranked tōshō" who forge swords that receive higher appraisal classifications, and the reality is that young tōkō must build a track record in order to obtain high-quality tamahagane reliably. Furthermore, the quality of tamahagane varies subtly with each operation, and the distribution of carbon content and impurities affects the difficulty of tanren and the appearance of the final hamon. Securing high-quality tamahagane has become a strategic challenge on a par with skill itself.

In recent years, international demand for tamahagane — purchase requests from non-Japanese tōshō who make Japanese swords — has also emerged, raising concern about further pressure on the domestic supply.

Depletion of Natural Whetstone Sources

The polishing of Japanese swords involves a multi-stage finishing process, from rough whetstones through natural finishing stones such as uchigumori and narutaki. These whetstones have been quarried from mountain areas in Kyoto, Nara, Shiga, Fukushima, and elsewhere, but many of these sources are reaching the limits of their extractable supply.

High-quality natural finishing stones used for the final polish, such as uchigumori-do and narutaki-do, have become particularly difficult to obtain, and both togishi and tōshō strongly feel the growing scarcity of their stocks. The amount of whetstone used to polish a single sword is not large, but a considerable quantity is needed for work throughout the year, and prices have been trending upward.

In response to this situation, the development of synthetic whetstones has advanced. Synthetic whetstones that reproduce the particle size distribution, softness, and grinding characteristics of natural whetstones are already commercially available and have reached a practical stage. However, many togishi insist on "a depth of blade texture that only natural stones can produce," and widespread adoption of technical substitutes requires a unified understanding within the industry.

Difficulty Procuring Forge Charcoal

The forging process requires large quantities of charcoal, and in particular the hard charcoal fired at high temperatures known as shirozumi (white charcoal) is well suited to it. Binchōtan is the leading variety, but stable supply of high-quality forge charcoal has become difficult due to the aging of charcoal makers, a shortage of successors, and problems with resource management of ubamegashi, the raw wood used.

Some tōshō secure multiple procurement routes for charcoal and make arrangements to handle variations in quality. Others have begun improving their forges and reviewing their work processes to increase charcoal consumption efficiency. Because charcoal quality directly affects temperature control during tanren, this is an important procurement challenge not only in terms of material cost but also in a technical sense.

Problems with Peripheral Materials Such as Lacquer, Wisteria, and Same-kawa

Sword making does not end with the blade alone; multiple craftspeople are involved, including saya makers, tsuka wrappers, and lacquer workers. The materials these craftspeople use — hon-urushi, wisteria vine, and same-kawa — are also materials whose sustainable domestic supply has become difficult.

The domestic share of hon-urushi is only a few percent, with the current situation being one of dependence on Chinese-produced lacquer for most of it. Wisteria vine is difficult to supply stably unless the rural mountain environment from which it can be harvested is properly maintained. Same-kawa (which is actually ray skin) relies on imports for much of its domestic demand. Many of the materials that support the sword as a comprehensive craft object have vulnerabilities in their supply chains.

Responses by Modern Tōshō

Responses to material constraints differ among individual tōshō, but several directions are visible.

• Building direct relationships with sources and producers: An increasing number of tōshō are forming long-term trading relationships with charcoal makers, lacquer farmers, and whetstone quarriers to secure stable supply.
• Inventory management and advance procurement of materials: When high-quality materials come onto the market, they are purchased in bulk and stored long-term in the workshop. For whetstones in particular, securing several years' worth of stock is becoming standard practice.
• Testing alternative materials and technical adaptation: Flexibility is required to adapt technique to changes in materials — such as the trial introduction of synthetic whetstones to replace natural ones, and the use of imported charcoal.

The raw materials issue is a challenge that relates to the sustainability of the traditional techniques of the Japanese sword itself. To protect the Japanese sword as a cultural form, what is needed in the long term is social support for the material supply side — tatara smelting, the natural whetstone industry, charcoal making — and the development of a market environment in which tōshō can procure materials at appropriate prices.

Conclusion: A Crisis of Materials Is a Crisis of Culture

The situation in which all three raw materials — tamahagane, natural whetstones, and forge charcoal — are simultaneously becoming difficult to procure is exerting quiet pressure on the maintenance of the Japanese sword as a traditional craft. If the industry behind each material declines, the very arena in which tōshō can apply their skills will be lost. All those involved in sword culture need to recognize that the preservation of traditional techniques cannot be completed by "nurturing tōshō" alone, but is inseparable from the continued existence of the craftspeople and industries that produce and supply the materials. As the culture of purchasing and appreciating Japanese swords online spreads, knowing the chain of material supply behind each single sword becomes an entry point to a deeper understanding of sword culture.